CN216518158U - Slide valve structure of screw expander - Google Patents

Abstract

The utility model relates to the technical field of screw expanders, in particular to a slide valve structure of a screw expander, which can realize the online adjustment of the expansion ratio of the screw expander and meet the requirements of different customer working conditions.

Description

Slide valve structure of screw expander

Technical Field

The utility model relates to the technical field of screw expanders, in particular to a slide valve structure of a screw expander.

Background

The screw expander is a heat engine which drives a screw rotor to rotate by means of gas volume expansion and converts heat energy into mechanical energy, is a new power machine which is developed in the 21 st century, can directly drive a generator, and can also directly drive mechanical equipment such as a pump, a fan and the like.

At present, the mainstream screw expander in the market is usually designed according to the requirements of customers in a customized manner, and any under-expansion or over-expansion can cause irreversible loss of a high-pressure heat source, so that the energy conversion rate is low. The specific principle is shown in figure 1, and ideally, the recoverable technical work of the thermodynamic system in the isentropic adiabatic expansion process is a part a-b-c-d-a. If the selected heat engine (i.e., screw expander, the primary parameter expansion volume ratio) does not match the desired thermodynamic process, either over-expansion or under-expansion occurs. Under the under-expansion working condition, the recoverable technical work of the thermodynamic system is an a-b-e-f-a part, which means that heat energy is not fully converted and utilized, and the f-e-c-d-f part is still wasted, so that the energy recovery efficiency is low. Under the over-expansion working condition, the first half section is power expansion in the working medium expansion process, technical work is output, the second half section is resistance expansion, power is consumed, the elimination length is equal, and finally, the utilized technical work is a part a-b-c-d-a minus a part c-n-g-c, and energy loss is caused. Furthermore, over-expansion tends to cause the expander to fail to operate properly.

The design of the slide valve of the expander is to solve the problems of over expansion or under expansion. The splayed opening of the air inlet of the air cylinder is enlarged or reduced through the movement of the slide valve, and finally the expansion ratio of the screw expander is realized, but the structure of the splayed opening is set when the screw expander is delivered from a factory. Because the pressure and the temperature of the working medium on the spot of the client are complicated and changeable, the design parameters are not matched, the adjustment of the volume ratio can not be met, even the expansion machine can not normally operate, the equipment has to be transformed back to the factory, the work is not done by mistake and the time is wasted, and unnecessary economic loss is caused.

Disclosure of Invention

The utility model provides a slide valve structure of a screw expander, which can realize the online adjustment of the expansion ratio of the screw expander and meet the requirements of different working conditions of customers in order to solve the problems that the expansion ratio of the conventional screw expander is difficult to adjust and cannot meet the requirements of the customers on different working conditions.

The technical scheme is as follows: a slide valve structure of a screw expander comprises a shell, wherein a rotor cavity and a slide valve cavity are arranged in the shell, the slide valve cavity is communicated with an expander inlet on the shell, an air inlet communicated with the slide valve cavity is formed in the rotor cavity, a movable slide valve is arranged in the slide valve cavity, and the slide valve structure is characterized in that two rows of through holes arranged on two sides of the center line of the slide valve are arranged on the rotor cavity,

the slide valve is further characterized in that the number of the two rows of through holes is consistent, the through holes are arranged in a splayed manner in a left-right one-to-one correspondence manner, a notch is formed in the end part of the slide valve, and the notch and the through holes are arranged in a splayed manner in a corresponding manner;

the through holes are kidney-shaped grid holes or round holes in rows;

the through hole is formed by casting or milling cutter machining;

an axial guide groove is formed in the sliding valve, and a guide pin matched with the axial guide groove is installed on the inner wall of the shell;

the outer peripheral surface of the sliding valve is in clearance fit with the inner wall of the sliding valve cavity, and a piston ring is arranged on the outer peripheral surface of the sliding valve and is made of PTFE material;

the sliding valve is fixedly connected with one end of a sliding valve rod, the other end of the sliding valve rod penetrates through the sealing cavity and is connected with one end of a screw rod positioned in the transmission cavity, a transmission screw rod sleeve is sleeved outside the screw rod and is installed on the shell through a bearing to realize rotation but axial movement incapability, and one end of the transmission screw rod sleeve is exposed out of the shell and is fixedly provided with a hand wheel;

a framework oil seal and an elastic retainer ring are arranged between the other end of the transmission screw sleeve and the outer peripheral surface of the sliding valve rod;

a main stuffing box is arranged between the seal cavity and the sliding valve cavity, an auxiliary stuffing box is arranged between the seal cavity and the transmission cavity, seal stuffing is arranged in the main stuffing box and the auxiliary stuffing box, and the sliding valve rod penetrates through the main stuffing box and the auxiliary stuffing box;

and the connecting end surface of the sliding valve cavity and the sealing cavity is provided with an O-shaped ring and a pressure relief groove communicated with the outlet of the expansion machine.

After the utility model is adopted, the slide valve moves to cover different through holes, and air inlet sections with different sizes are formed in principle, so that the online adjustment of different expansion volume ratios is realized, the structure is simple, the processing is convenient, and the requirements of different customer working conditions are met.

Drawings

FIG. 1 is a prior art over-or under-expansion schematic;

FIG. 2 is a schematic structural view of the present invention;

FIG. 3 is a side view of the rotor and spool cavities;

FIG. 4 is a schematic view of a slide valve configuration;

FIG. 5 is a schematic view of a first state of expansion volume ratio adjustment;

FIG. 6 is a schematic view of a first state of expansion volume ratio adjustment;

FIG. 7 is a schematic view of a first state of expansion volume ratio adjustment;

FIG. 8 is a schematic view of a first state of expansion volume ratio adjustment;

fig. 9 is a graph of expansion volume ratio.

Detailed Description

As shown in fig. 2 to 4, a slide valve structure of a screw expander includes a housing 1, a rotor cavity 3 and a slide valve cavity 4 are arranged in the housing 1, the slide valve cavity 4 is communicated with an expander inlet 7 on the housing 1, an air inlet 15 communicated with the slide valve cavity 4 is arranged on the rotor cavity 3, a movable slide valve 6 is installed in the slide valve cavity 4, two rows of through holes 16 arranged on two sides of a center line of the slide valve 6 are arranged on a cavity wall of the rotor cavity 3, the through holes 16 are arranged in a shape of a Chinese character 'ba', the left and right sides of the through holes are in one-to-one correspondence, a notch 17 is arranged at an end of the slide valve 6, the notch 17 is in a shape of a Chinese character 'ba' corresponding to the through hole 16, one end of the air inlet 15 is a plane, the other end of the air inlet is in a shape of a Chinese character 'ba' matching with the notch 17, in this embodiment, three groups of through holes 16 are arranged, and the air inlets 15 are added, so as to realize adjustment of expansion volume ratios of four stages, i =3.6, Vi =3.0, Vi =2.5 and Vi =2.2, as shown in fig. 5 to 8, the schematic diagram is shown in fig. 9; the through holes 16 may be kidney-shaped gate holes or circular holes in rows, and the present embodiment shows a kidney-shaped gate hole structure. The through hole 16 is formed by casting or milling, and if formed by milling, it can be vertically processed by using a milling cutter.

The sliding valve 6 is designed in a cylindrical piston mode, the peripheral face of the sliding valve 6 is in clearance fit with the inner wall of the sliding valve cavity 4, the piston ring 5 is installed on the peripheral face of the sliding valve 6, the piston ring 5 is made of PTFE materials, and the piston ring 5 is located and supported, so that the power consumption of axial sliding can be reduced. And the slide valve 6 is provided with an axial guide groove 20, and the inner wall of the shell 1 is provided with a guide pin 2 matched with the axial guide groove 20, so that the slide valve 6 can be effectively controlled to only move axially.

The slide valve 6 is fixedly connected with one end of a slide valve rod 8, the other end of the slide valve rod 8 penetrates through a sealing cavity 9 to be connected with one end of a screw 27 located in a transmission cavity 26, a transmission screw sleeve 21 is sleeved outside the screw 27, the transmission screw sleeve 21 is installed on the shell 1 through a bearing to be rotatable but incapable of axially moving, one end of the transmission screw sleeve 21 is exposed out of the shell and fixedly provided with a hand wheel 24, the transmission screw sleeve 21 rotates in place through rotating the hand wheel 24, and the screw 27 axially moves, so that the axial position adjustment of the slide valve 6 is realized, and different through holes 16 are shielded to realize the adjustment of the volume ratio. In the figure, 18 is an exhaust end cover, 19 is an exhaust side cover, and a sealing end cover 23 is tightly installed on the exhaust side cover 19 through a bolt 13 to form a rigid wall. A framework oil seal 29 and an elastic retainer ring 30 are arranged between the other end of the transmission screw sleeve 21 and the outer peripheral surface of the slide valve rod 8, a framework oil seal 29 is also arranged at the hand wheel 24, and an oil-free bushing 25 is also arranged. A main packing box 10 is arranged between the seal cavity 9 and the sliding valve cavity 4, an auxiliary packing box 32 is arranged between the seal cavity 9 and the transmission cavity 26, seal packing 11 is installed in the main packing box 10 and the auxiliary packing box 32, a gland 12 is arranged at the end of the main packing box 10 and is fixed by a bolt 13, O-shaped rings 22 are arranged outside the main packing box 10 and the auxiliary packing box 32, the sliding valve rod 8 penetrates through the main packing box 10 and the auxiliary packing box 32, and the packing 11 is made of flexible graphite. The sealed cavity 26 is provided with a sealed cover plate 14 to form a sealed cavity which can be filled with replacement gas or only emptied at a high point, so that the effective isolation of medium gas and lubricating oil can be realized.

The connecting end face of the sliding valve cavity 4 and the sealing cavity 9 is provided with the O-shaped ring 22 and a pressure relief groove 28 communicated with the expander outlet 31, so that even if the O-shaped ring 22 fails, the high-temperature and high-pressure heat source medium in the sliding valve cavity 4 can only leak to the expander outlet 31 with low pressure and low temperature, and the sealing reliability is ensured. In the figure 33 the rotor is in the rotor chamber 2 and 34 is a plug.

Claims (10)

1. The utility model provides a screw rod expander slide valve structure, its includes the casing, set up rotor chamber and slide valve chamber in the casing, the slide valve chamber intercommunication expander entry on the casing, set up the intercommunication on the rotor chamber the air inlet of slide valve chamber, install mobilizable slide valve in the slide valve chamber, its characterized in that, be provided with two rows on the rotor chamber and arrange in the through-hole of the central line both sides of slide valve.

2. The slide valve structure of the screw expander according to claim 1, wherein the two rows of through holes are in the same number and are arranged in a splayed shape corresponding to each other one by one, and a notch is formed at the end of the slide valve and corresponds to the through hole in a splayed shape.

3. The slide valve structure of a screw expander according to claim 1, wherein the through-holes are kidney-shaped grid holes or rows of round holes.

4. The slide valve structure of a screw expander according to claim 1, wherein said through hole is formed by casting or milling.

5. The slide valve structure of the screw expander according to claim 1, wherein the slide valve is provided with an axial guide groove, and a guide pin matched with the axial guide groove is installed on the inner wall of the housing.

6. The sliding valve structure of screw expander according to claim 1, wherein the outer peripheral surface of the sliding valve is in clearance fit with the inner wall of the sliding valve cavity, and the outer peripheral surface of the sliding valve is provided with a piston ring, and the piston ring is made of PTFE material.

7. The slide valve structure of the screw expander according to claim 1, wherein the slide valve is fixedly connected with one end of a slide valve rod, the other end of the slide valve rod penetrates through a sealing cavity to be connected with one end of a screw rod positioned in a transmission cavity, a transmission screw sleeve is sleeved outside the screw rod, the transmission screw sleeve is mounted on the shell through a bearing to realize rotation but cannot move axially, and one end of the transmission screw sleeve is exposed out of the shell and fixedly provided with a hand wheel.

8. The slide valve structure of a screw expander according to claim 7, wherein a frame oil seal and a circlip are provided between the other end of the drive screw housing and the outer peripheral surface of the slide valve stem.

9. The slide valve structure of the screw expander according to claim 7, wherein a main stuffing box is arranged between the seal cavity and the slide valve cavity, an auxiliary stuffing box is arranged between the seal cavity and the transmission cavity, seal stuffing is arranged in the main stuffing box and the auxiliary stuffing box, and the slide valve rod penetrates through the main stuffing box and the auxiliary stuffing box.

10. The sliding valve structure of the screw expander according to claim 7, wherein an O-shaped ring is arranged on the connecting end surface of the sliding valve cavity and the sealing cavity, and a pressure relief groove communicated with the outlet of the expander is formed.

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